Temperature-compensated interrupter firing circuit

Abstract

In one example, a circuit interrupter includes a bus bar configured to conduct a current and configured to connect to an electrical grid. The circuit interrupter includes a bus bar cutter configured to sever the bus bar, a temperature compensation circuit including a resistance-temperature-coefficient (RTC) circuit configured to provide a temperature-compensated delay, and a detonator firing circuit configured to trigger the bus bar cutter in response to the temperature-compensated delay. The temperature-compensated delay is based on a voltage across a resistance temperature detector (RTD).

What is claimed is: 
     
         1 . A circuit interrupter comprising:
 a bus bar configured to conduct a current, the bus bar configured to connect to an electrical grid;   a bus bar cutter configured to sever the bus bar;   a temperature compensation circuit including a resistance-temperature-coefficient (RTC) circuit configured to provide a temperature-compensated delay; and,   a detonator firing circuit configured to   trigger the bus bar cutter in response to the temperature-compensated delay,   wherein the temperature-compensated delay is based on a voltage across a resistance temperature detector (RTD).   
     
     
         2 . The circuit interrupter of  claim 1 , wherein the RTC circuit includes
 a current regulator;   a first resistor connected to the current regulator;   a resistor capacitor network connected to the current regulator; and,   an integrated circuit configured to measure the voltage across the RTD.   
     
     
         3 . The circuit interrupter of  claim 2 , wherein the temperature-compensated delay is based on the voltage measured across the RTD. 
     
     
         4 . The circuit interrupter of  claim 2 , wherein the resistor capacitor network includes
 a capacitor connected to the current regulator;   a second resistor connected between the current regulator and the capacitor; and,   a third resistor connected in parallel with the RTD.   
     
     
         5 . The circuit interrupter of  claim 2 , wherein the resistor capacitor network is configured to cause the temperature-compensated delay to remain constant as a temperature of the RTD changes. 
     
     
         6 . The circuit interrupter of  claim 1 , wherein the bus bar is configured to displace as a result of being severed. 
     
     
         7 . The circuit interrupter of  claim 6 , wherein a severing of the bus bar causes a commutation of the current into a current limiting fuse for a predetermined period. 
     
     
         8 . A system comprising:
 a temperature compensation circuit including a resistance-temperature-coefficient (RTC) circuit configured to provide a temperature-compensated delay for a bus bar cutter configured to sever a bus bar;   a detonator firing circuit configured to trigger the bus bar cutter in response to the temperature-compensated delay,   wherein the temperature-compensated delay is based on a voltage across a resistance temperature detector (RTD).   
     
     
         9 . The system of  claim 8 , further including a current sensing circuit configured to turn on the RTC circuit in response to detecting a predetermined amount of current being conducted across the bus bar. 
     
     
         10 . The system of  claim 9 , wherein the RTC circuit includes
 a current regulator;   a first resistor connected to the current regulator;   a resistor capacitor network connected to the current regulator; and,   an integrated circuit configured to measure the voltage across the RTD.   
     
     
         11 . The system of  claim 10 , wherein a severing of the bus bar causes a commutation of the current into a current limiting fuse for a predetermined period. 
     
     
         12 . The system of  claim 11 , wherein triggering the bus bar cutter in response to the temperature-compensated delay includes triggering the bus bar cutter at an expiration of the temperature-compensated delay. 
     
     
         13 . The system of  claim 10 , wherein the resistor capacitor network includes
 a capacitor connected to the current regulator;   a second resistor connected between the current regulator and the capacitor; and,   a third resistor connected in parallel with the RTD.   
     
     
         14 . The system of  claim 10 , wherein the resistor capacitor network is configured to cause the temperature-compensated delay to remain constant as a temperature of the RTD changes. 
     
     
         15 . A method of controlling a circuit interrupter comprising:
 measuring, via a current sensing circuit, an amount of current being conducted across a bus bar;   providing, via a temperature compensation circuit including a resistance-temperature-coefficient (RTC) circuit, a temperature-compensated delay for a bus bar cutter configured to sever a bus bar; and,   triggering, via the temperature compensation circuit, the bus bar cutter in response to the temperature-compensated delay,   wherein the temperature-compensated delay is based on a voltage across a resistance temperature detector (RTD).   
     
     
         16 . The method of  claim 15 , wherein triggering the bus bar cutter in response to the temperature-compensated delay includes triggering the bus bar cutter at an expiration of the temperature-compensated delay. 
     
     
         17 . The method of  claim 15 , wherein the RTC circuit includes
 a current regulator;   a first resistor connected to the current regulator;   a resistor capacitor network connected to the current regulator; and,   an integrated circuit, and   wherein the integrated circuit is configured to measure the voltage across the RTD.   
     
     
         18 . The method of  claim 17 , further including commutating, via a current-limiting fuse, the current for a predetermined period. 
     
     
         19 . The method of  claim 17 , wherein the resistor capacitor network includes
 a capacitor connected to the current regulator;   a second resistor connected between the current regulator and the capacitor; and,   a third resistor connected in parallel with the RTD.   
     
     
         20 . The method of  claim 17 , wherein the resistor capacitor network is configured to cause the temperature-compensated delay to remain constant.